Electrohydraulic system for elevator brakes and the like



0a. 14, 1930. H. B. GOLDMAN ELECTROHYDRAULIC SYSTEM FOR ELEVATOR BRAKES AND THE LIKE Filed Nov. 9, 1928 INVENTOR Hang/l3. Goldman i 10 In electric elevator installations, it is cushydraulic pump-pressure to force open the 3 ATES HARRY GOLDMAN, F BROOKLINE, PENNSYLVANIA ELECTROHYDBAULIC SYSTEM FOR ELEVATOR'BRAKES AND TEE LIKE Application filed November 9, 1928. Serial No. 318,137.

My invention is particularly designed for ling equipment is energized only when the the operation of brakes for controlling elevamain elevator motors are energized. tors, although it is susceptible of other uses. More particularly, my invention provides The principal object of my invention is to a combined electrical and hydraulic or pneuprovide anew brake system for replacing less matic brake-controlling system in which a 55 desirable brake systems, and particularly for pump is connected to the motor which is enerreplacing the alternating-current electromagglzed only when the brake is to be released; nets for releasing the brakes in alternating and any suitable piston, bellows or diaphragm current elevator installations. arrangement is utilized for responding to the tomary to provide a pring actuated brake bralre-shoes against the action Of their closing which is normally applied to a driving shaft p gof the elevator and Which is released by an h r O JBQ of my Invention is to proelectromagnet, which is energized whenever vide means for quickly stopping, or even temthe main elevator motors are energized in porarily reversing, the motor which actuates C5 either direction, and which is deenergized 'b r k wontrollingequipment.

When the control switch in the elevator car is Vvlth i eg g Pther Objects in returned to its mid-position or, in general, vlew, y e q conslsts 1n t pp at s, when the main elevator motors are deenersystems and circuit arrangements hereinafter 20 j d, described and claimed and illustrated in the Alternating-current brake-releasing magpa y g f g, h r ln nets which are available for use in alternat- The slngle figure 1S dlagmmmatlc ing-current elevator systems invariably in- Showing P in Section, i1h1$triting 'p volve the use of dashpots which are notoriousferred embodiment of y lnventlfm. ly unreliable; they are exceedinglynoisy,grip- Shown 1n the drawlngb y lnYePtlon 1S p y in their action, not readily adjustable, and gpp h an QIQVatPI brake 5 compnslng two liable to burn out if they stick when the arma- 095 6 bearlng on t break ture is not in engagement with its polemieces pulley 7 mounted on the main elevator drive 90 besides being unwarrantably high in cost. i i fi Shoes are mounted on In dlrect-current elevator installations, less e eams together y trouble is experienced with the direct-current means of a,bmke'-actuat1ng P Pg 11 Whlch brakemeieasing magnetts but thgy are Still norilnaclily brasses the brake 5 to its closed or si f to lgany fii g gfi p p i 1 tamong li: m dgr i s fiii controlling the operation of M w ma emen ione eir 1g cos g g p g i g trans ersdata ases:

W e a mo or w 10 1s cons an y running whenever the elevator: is in condition, for opi s' g s l' i g fi whlqh erat-ion, whether it is standing still or moving, z fgg l i e m and to ut1l1ze such motor for energizing the h k p h Pagemen w} brake-controlling equipment of the elevator. t 5 gt or 3 3 3 g g y srchsystemsmpmticallyOutofthequesaaaeayaezrzfizzanalgesia? however aqcount of t losses m The motor drives a pump 13 which is pref- P and depr 9 resulimg from the erabl'y of a type which has the inherent char- '5 contlnuous operatlqn of sald motor even acteristic of maintaining a predetermined when elevator 15 l 1d19 as It y be limited static pressure-head during its operafor long intervals during the day. 1 tion. For this purpose, some types of cen- My invention overcomes the foregomg and trifugal pumps have been found very satisother difficulties by prov1d1ng a system wherefactory, as shown in the drawing, although C0 by a motor for energizing the brake-controlcare has to be taken, in the selection of a cen- 1 v comprises an shaft, as is well known in the art.

trifugal pump, to avoid those pumps which will not develop any pressure-head against a static load, or when the movement of the liquid through the pump is blocked. In general, a pump such as that just mentioned, impeller mounted on a rotating The pump 13 draws the oil or other liquid from a reservoir 14 and'applies it, under suitable pressure, to a'hydraulic brake cylinder 15, where a suitable arrangement of pistons, bellows or diaphragms is provided for actuating a pair of plunger-rods 17 through a sufficient distance to release the brake. As shown in the drawing,rubber diaphragrns 18 are provided, which press against plungerheads 19 carried by the plunger-rods 17 The length of the plunger stroke, and hence the force applied to the brake, may be regulated by means of a threaded collar 21, and the op eration may be still further adjusted by controlling the loose play between the plungerrods17 and the brake arms 9, as by means of adjusting-bolts 22 on the ends of the plunger-rods 17.

In operation, the hydraulic pump 13, as soon as it is rotated, withdraws a small quantity of oil or'other liquid from the. reservoir 14 and applies it at considerable pressure, through a the pump 13 and the hydraulic brake cylinder 15, forcing out the plunger rods 17 against the brake beams 9, and reducing the oil level in the reservoir to a posltion such as indicated by dotted lines 26. t

In a system such as that just described, it is usually necessary to provide means for expediting the release of the hydraulic pressure when the motor 12 is deenergized, as the motor has considerable inertia, and the brakes must be applied with as little delay as possible, particularly where inching must be resorted to, in leveling the elevator car with respect to the floors of the building.

In the drawing, Lhaveshown a preferred means for expediting the releasing of' the brake-opening means, which consists in quickly stopping the motor 12, or even temporarily reversing the same. The motor is normally controlled means of an electromagnetic switch or relay 27 having main contacts 28 which energize the motor in the forward direction whenever the relay is actuated to 'closed position.

' According to the system shown in the drawing, back contacts 29 are provided on the electromagnetic relay 27, so that whenever the relay is'deenergized, the back contacts are closed the motor 12.' Additional means are provided, however, for preventing the energization of the motor in the reverse direction, except when the elevator-brake is in its open or released position with the shoes 6 out of engagement with the brake wheel or pulley 7. Such additional means is shown its full speed and causes discharge pipe 24 which connects 1 draulic mechanism.

as a switch 31 which is mechanically operated in accordance with the position of the plunger-rods 17 of the'hydraulic plunger mechanism, as by means of a collar 32 on the righthand plunger-rod 17, engaging an actuating lever 33 on the switch 31.

The electrical operation of the system shown in the drawing is as follows. The electromagnetic relay 27' is actuated by any suitable means, which is intended to be symbolized by the push-button 34, although, in general, it will be understood that the energizing circuit of this relay is coupled to the main elevator motors (not shown) or to the controller in the elevator car (not shown) so as to be energized when the control handle is in either the forward or the reverse position, and deenergized when the control handle is in its mid-position.

\Vhen the electromagnetic relay 27 closes, it energizes the pump motor 12 in its normal pumping or forward direction and, as full voltage is immediately applied to the mo-- almost instantaneously to the pump to immediately develop suflicient oil-pressure to retract the brake shoes and thus to release the brake from the main elevator drive shaft 8 against the force of the spring biasing means tor, it accelerates It will be understood that, when the brake is relea'sed, the mechanically-coupled switch 31 in the reversing circuit of the motor is closed, but nothing happens because this reversing circuit also includes the back-contacts 29 on the electromagetic relay 27, which are open whenever the relay is in its energized osition.

When the electromagnetic switch 27 is deenergized, the normal energizing circuit of the pump-motor 12 is interrupted, and the back-contacts 29 of the relay close, so as to apply full line-voltage to the motor 12, in reverse phase-sequence, thus almost instantaneously stopping the motor and starting it rotating a few revolutions in the reverse direction. The temporary reverse rotation of the motor is desirable in order to facilitate the flow of the oil from the hydraulic brake cylinder 15 back into the reservoir 14, thus quickly deenergizing the pistons 17 of the hy- This is necessary because the restricted openings in the pump 13 would otherwise retard the back flow of oil through it if the pump were not reversed, and would thus retard the return of the brake shoes to their normal biased position in engagement with the brake wheel 7. It will be, understood that only a small quantity of 32 on the plunger-rod 17 of the hydraulic. mechanism, opens, thus deenergizing the pump motor 12.

While I have illustrated means for momentarily reversing the pump, in order to expedite the return of oil from the hydraulic pressure-cylinder 15 to the reservoir 14, it is to be understood that any other suitable means for performing this function may be utilized, although, at present, I prefer the means shown in the drawing.

It will be seen, from the foregoing description, that I have developed a particularly quiet brake which is capable of developing enormous pressures almost instantaneously, in a mechanism embodying the utmost in simplicity and reliability, developing not a single defect or failure even after a quarter of a million operations in the test laboratory.

While I have illustrated my invention in a preferred embodiment, I wish it to be understood that such illustration is intended only to be suggestive, and not as limiting my invention to the particular embodiment shown. I desire, therefore, that the appended claims shall not be limited except as required by the language thereof when read in the light-of the prior art.

I claim as my invention:

1. The combination with a movable element normally biased to one position, of an electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted position, and means for applying a force bringing said motor to a quick stop when said element to be returned to its biased position.

2. The combination with ,a movable element normally biased to one position, of a reversible electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for start- 'ing and stopping said motor, means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted position, and means for momentarily reversing said motor when said element is to be returned to its biased position, whereby said force-developing means may be more quickly moved so as to allow the biasing means to morequickly return said element to its biased position.

3. The combination with a movable element normally biased to one position, of a reversible electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor,means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted position, and means for momentarily reversing said motor when said element is to be returned to its biased position, whereby said force-developing means may be more quickly moved so as to allow the biasing means to more quickly return said element to its biased position, said reversing means including means responsive to the return of said element for interrupting the reversing circuit of the motor.

4. The combination with a movable element normally biased to one position, of an electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, retracting means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted positon, and auxiliary means operative at the moment of the interruption of the normal energizing circuit of said motor to develop a reverse force and apply the same to said retracting means, whereby the biasing means may more quickly return said element to its normal position.

5. An electro-hydraulic brake system comprising a springapplied brake, an electric motor, means for energizing and deenergizing the motor, a hydraulic pressure-responsive means for releasing said brake, a liquid reservoir, and an impeller pump driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, said pump itself inherently having the characteristic of maintaining a predetermined lirnited static pressure-head during its operation.

6. An electro-hydraulic brake system comprising a. spring-applied brake, an electric motor. switch for energizing and deenergizing the motor, a hydraulic pressure-responsive means for releasing said brake, a liquid reservoir, an impeller-type pumping apparatus driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, said pumping apparatus itself having the characteristic of maintaining a predetermined limited static pressure-head during its operation, and auxiliary means operative at the moment of the interruption of the normal energizing circuit of said motor to expedite the return of the liquid from said pressure-responsive means to said reservoir.

7. An electro-hydraulic brake system comprising a spring-applied brake, an electric motor, a switch for energizing and deenergizing the motor, a hydraulic pressure-1e sponsive means for releasing said brake, a liquid reservoir, an impeller-type pump driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, said pump having the characteristic of maintaining a predetermined limited static pressure-head during its operation, and means for bringing said motor to a quick stop When the brake is to be applied.

8. An electro-hydraulic brake system comprising a spring-applied brake, a reversible electric motor, a switch for energizing and deenergizing the motor, a hydraulic pressure-responsive means for releasing said brake, a liquid reservoir, a pumping apparatus driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, said pumping apparatus having the characteristic of maintaining a predetermined limited static pres sure-head during its operation, and auxiliary means operative at the moment of the interruption of the normal energizing circuit of said motor to momentarily reverse said motor.

9. An electro-hydraulic brake system comprising a spring-applied brake, a reversible electric motor, a switch for energizing and deenergizing the motor, a hydraulic pressure-responsive means for releasing said brake, a liquid reservoir, a pump driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, auxiliary means operative at the moment of the interruption of the normal energizing circiut of said motor to momentarily reverse said motor, said reversing means including means responsive to the re-application of the brake for interrupting the reversing circuit of the motor.

10. The combination with a movable ele-.

ment normally biased to one position, of an electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, means responsive to the rotation of said motor for developing a force,

and applying it in such manner as to move said element to said retracted position, said last-mentioned means comprising: a pump actuated by said motor, means responsive to the pump-pressure for moving said element to said retracted position and holding it there against the action of its biasing means, and means for applying a force bringing said motor to a quick stop when said movable element is to be returned to its biased posi-.

tion.

11. The combination with a movable element normally biased to one position, of an electric motor adapted said element is to be retracted-to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, means responsive to the rotation of said motor for developing a force and applying it in such manner as to move tion and holding it there to be operated when said element to said'retracted position, said last-mentioned means comprising: a pump actuated by said motor, means responsive to the pump-pressure for moving said element to said retracted position and holding it there against the action of its biasing means, and auxiliary means operative immediately upon the interruption of the normal energizing circuit of said motor to apply a reverse liquid pressure, thereby expediting the flow of fluid from said pump-pressure-responsive means.

12. The combination with a movable element normally biased to one position, of a reversible electric motor adapted to be operated when said element is to be retracted to a different position and'stopped when said element is in its biased position, means for starting and stopping said motor, means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted position, said last-mentioned means comprising: a pump actuated by said motor, means responsive to the pump-pressure for moving said element to said retracted position and holding it? there against the action of its biasing means, and means operative at the momentof the interruption of the normal energizing circuit of said motor to reverse said motor.

13. The combination with a movable element normally biased to one position, of a reversible electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, means responsive to the rotation of said motor for developing a force and applying it in such manner as to move said element to said retracted position, said last-mentioned means comprising: a pump actuated by said motor, means responsive to the pump-pressure for moving said element to said retracted posiagainst the action of its biasing means, means operative at the moment of the interruption of the normal energizing circuit of said motor to reverse said motor, and means operative upon the return of said element to its normal biased position for interrupting the reversing circuit of the motor.

14. The combination with a movable element normally biased to one position, of an electric motor adapted to be operated when said element is to be retracted to a different posit-ion and stopped when said element is in its biased position, means for starting and stopping said motor, retracting means responsive to the rotation of said motor for moving said element to a different position, andrauxiliary means, coming into operation at the moment of the interruption of the normal energizing circuit of said motor and While the motor still has considerable speed,

to produce and apply a force in a direction to deenergize said retracting means.

15. The combination with a movable element normally biased to one position, of an electric motor adapted to be operated when said elementis to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor. retracting means responsive to the rotation of said motor for movingsaid element to a different position, and auxiliary means, initially coming into operation at the moi-nent of the interruption of the normal energizing circuit of said motor and while the motor still has considerable speed, to derive a force from said motor tending to expedite the movement of the retracting means to normal deenergized position.

16. The combination with a movable element normally biased to one position, of an electric motor adapted to be operated when said element is to be retracted to a different position and stopped when said element is in its biased position, means for starting and stopping said motor, retracting means responsive to the rotation of said motor for moving said element to a difierent position, said last-mentioned means comprising: an impeller pump actuated by said motor, said pump itself inherently having the characteristic of maintaining a predetermined limited static pressure-head during its operation, means responsive to the pump-pressure for moving said element to said retracted position and holding it there against the action of its biasing means, and auxiliary means operative at the moment of the interruption of thenormal energizing circuit of said motor to quickly pass the fluid from said pumppressure responsive means.

17. A hydraulic system comprising a prime mover, an impeller pump driven thereby, said pump itself having the characteristic of maintaining a predetermined limited pressure-head during its operation, a pressure-responsive device. and means for applying said pump pressure head to said pressure-responsive device.

18. An electro-hydraulic brake system comprising a brake, an electric'motor, means for energizing and deenergizing the motor, a hydraulic pressure-responsive means for actuating said brake, a liquid reservoir, and an impeller pump driven by said motor and connected between said reservoir and said hydraulic pressure-responsive means, said pump itself inherently having the characteristic of maintaining a predetermined limited static pressure-head during its operation, the rotors of the pump and motor being rigidly mounted on the same shaft.

19. An electro-hydraulic brake system comprising a brake, an electric motor, means for energizing and deenergizing the motor, a hydraulic pressure-responsive means for HARRY B. GOLDMAN. 

